33 people were wounded by a bombing on Thursday during an amateur boxing match in a central Philippines province, the government said.

This is the second attack in Philippines on a public place by unknown perpetrators in less than a week.

On late Wednesday, an 81-millimetre mortar round was detonated remotely by a cellphone during the amateur bout outside a shopping mall in Leyte province, reports Reuters.

It followed a Christmas Eve grenade explosion outside a Catholic church that wounded 16 people on the southern island of Mindanao.

Mindanao is a Muslim-dominated region where a long-running insurgency is being fought.

Till now no suspects have been identified and no group has claimed any responsibility, the police said.

Police said there was no indication the two attacks were linked, says a report on Reuters.

President Rodrigo Duterte has warned of the threat of a proliferation of festering Islamist militancy in the Philippines and also of an infiltration by the Islamic State militant group if offensives succeed in driving its fighters out of Iraq and Syria, reports Reuters.

Duterte has also warned of vulnerability in the southern Philippines, where some splinter groups have pledged allegiance to Islamic State.